A new crystal form of MshB from Mycobacterium tuberculosis with glycerol and acetate in the active site suggests the catalytic mechanism

A new mechanism for hydrolysis of the amide bond in GlcNAc-Ins by MshB, which is supported by structural evidence, is proposed. In particular, the involvement of Tyr142, which was predicted on the basis of kinetic and mutagenic studies, is confirmed.